The invention relates to novel telluryl compounds, methods for preparing them and to novel intermediate products that can be applied for these methods, as well as to diagnostic preparations based on the novel compounds.
More in particular, but not exclusively, the invention relates to novel telluryl derivatives of steroids and, more in particular, to such compounds labelled with radioactive tellurium.
Preparations on the latter compounds may be applied for diagnostic investigation into abnormalities of internal organs as well as the radio-immunologic determination of the steroid content in bodily fluids such as blood or urine. The non-radioactively labelled novel telluryl compounds according to the invention can also be used for the determination of the steroid-level in bodily fluids.
For the diagnostic investigation into abnormalities of internal organs according to the "scintigraphic" method use has been made for several years, i.a. of steroids labelled with iodine-isotopes, such as cholesterol for the scanning of the adrenals.
Since the use of radioactively labelled iodine derivatives, such as .sup.131 I-iodine-cholesterol, for this purpose leads to undesirable irradiation load of the body, more in particular of the thyroid gland, mainly as a result of the .beta.-irradiation produced by these derivatives, it has been proposed to use compounds labelled with radioactive selenium for this purpose- see for selenium-cholesterol Netherlands Patent Application 75 02022 laid-open for public inspection (corresponding to UK patent application No. 7808/74).
Though because of the absence of .beta.-irradiation, the irradiation specificity of compounds labelled with radioactive selenium is more favourable than that from the derivatives that are suitable for the above purpose and that are labelled with radioactive iodine, the former labelled selenium compounds have also obvious drawbacks yet. In particular the proposed .sup.75 Se isotope yields a very complicated irradiation picture because it emits .gamma.-irradiations of very different energies, which upon scanning adversely affect the dissolution power. As a result it is not easy to obtain, with the dose of radioactive selenium maximally acceptable from a radiobiological point of view, an adequate picture of the organ to be "scanned," so that the diagnosis is seriously hampered.